I don't look at the Moon very often, although it really is fascinating. So, tonight I went out to the observatory expressly to spend the evening on the Moon. I used a 14" f/10 SCT and mostly the 14mm (254x) and 20mm (178x) ES100 eyepieces.

The first thing that happened was this: I was at 254x, and just by chance I was looking at exactly the right spot in the southern part of the Moon when something went right across my FOV. Maybe it was a satellite; but it was distinctly potato-shaped, and was about the same diameter as the crater Albategnius B. It moved west to east. Maybe a NEO? It passed across the Moon in about 2 seconds. This happened, as far as I can tell, at 21:01 MST on 8/13 (so it would be 04:01 UT on 8/14).

Then I looked at Ptolemaeus on the terminator. The crater floor was dark, but the high peaks were lit. Then suddenly, a ghostly, pale streak of fog appeared inside the crater, followed by three more. They were totally surrounded by dark. Of course, it was the dawn starting to peek between the mountain peaks; but it didn't look like that! It was very eerie looking. They continued to get brighter until they merged; but it was still very spooky looking by the time I lost the Moon.

You know that famous drawing Galileo made of the half-moon, that has a big crater showing on the terminator? After tonight, I'm positive the crater was Ptolemaeus.

Then, I went south, and saw the large, rectangular, blocky structure in the middle of Heraclites. It looked much larger in the low sun angle than it does in any of the atlases.

Southwest of this, I saw what I swear looked like a multi-ring basin structure, centered on the still-invisible Clavius. It seemed obvious, almost jumped out at me. Has this been discussed before? I've never heard of Clavius being a multi-ring basin. It's pretty easy to trace it out on the atlases, too.

A lot of this is probably old hat to many of you guys here; but as an infrequent lunie, it was all very captivating and special. I wish I knew what the potato was. And I love to hear some views about Clavius.

Very nice report Rick. The detail must've Ben dazzling through the 14!!! I will say I am disappointed though. The potato no doubt was a lunar chicken egg blasted into orbit no doubt from that recent night side lunar impact recorded not that long ago.

Ah, Pete Pete Pete,Everyone knows GLC's don't lay potatoes! Although a serious case of gas could propel a GLC egg into space, I suppose. Maybe that's what the flash on the dark side was - they're lighting their farts.

But seriously, is there any chance that Clavius has a multi-ring structure around it? Or was that all just an illusion?

Potato shaped objects, streaks? Rejoining and becoming brighter? Am I reading this right or do I need a sense of humor?

If you're being descriptive of lunar sun rise, well done!

Besides, I thoroughly discredited the Lunar chicken egg theory years ago, while not damaging the reputation of it's only proponent.

No humor intended in the original post. That was a description of sunrise in Ptolemaeus. The potato-shaped object was, well, I have no idea. It crossed the illuminated face of the Moon in about 2 seconds, suggesting it was pretty near the Earth. Maybe a NEO? Maybe just a satellite, but it seemed pretty big, and I never heard of a potato-shaped satellite. Nothing to do about this one except wonder what the heck it was.

Clavius was mostly illuminated tonight, and I'm still seeing an outer ring structure, about twice the diameter of Clavius. The "21st Century Atlas" chart 15 shows it really well. I've emailed some authories about it - could Clavius actually be part of a multi-ring basin system? I've found no mention of it in any of my books.

And "ring" external to Clavius is probably illusory. In smaller "large" craters like Clavius (<250km), ring structures, if present, are found *within* the primary topographic rim...iow, *inside* the crater itself. see: https://origin-ars.e...100203X-gr1.jpg For ring structures to form outside the crater rim a much more energetic impact would be required than that which created Clavius.

The only ring Clavius may have once had is what is termed a "central peak ring", iow a series of centrally located uplifts forming small circular formation. However little evidence is left of such in Clavius, probably due to such being buried/obscured by interior flows, impacts, etc.

Maybe so. The structure, once you look for it, is obvious. Maybe it's just chance alignments of unconnected features, a la the Martian canals. Look at the 21st Century Atlas chart 15; or better yet, at the Moon tonight. Do you see it?

Rick:I see exactly what you're talking about. It's evident on Rukl and photos. The drawings and photo give the effect of large moat around Clavius. Maginus and Longomontanus lie just outside, Blancanus and Sheiner in the moat. I haven't noted it in my scope, I'll look again tonight.

Now, if you were looking at Clavius last night, didn't you notice the "eye's" staring at you? Around 2100 Central time Clavius D & C had just the tops of the rims illuminated giving the impression of a couple of eyes from within Clavius.

Yes, i looked at some images & maps of what you reported before i posted, Rick. I *do* see what you are talking about and my use of the word "illusory" was not meant to refer to the alignments existence or visibility--a sort of ring shape is there alright-- but rather that the relationship of that to Clavius, morphologically, is illusory. Impacts capable of raising *external* rings, even one, don't begin until the impact crater get upwards of 400km or so...or so says the rather extensive literature on the subject...

Impacts capable of raising *external* rings, even one, don't begin until the impact crater get upwards of 400km or so...or so says the rather extensive literature on the subject...

Mardi,
Could you direct me to some of the better literature of this nature? Something an intelligent layman could understand (perhaps I flatter myself), but short of the hard, cold science that might be over my head? The most authoritative work I have at the moment is "Modern Moon". (Be gentle with me; I don't believe my comprehension level is as great as yours...)

A look last night gave a slight indication of this ring/moat structure. I'm sure it was better revealed earlier this week at local sunrise.

I have a completely uninformed theory about this Clavius outer ring business.

Here goes: The outer ring is a far more ancient impact structure, filled with lava flows but since pummeled and mostly leveled by the impacts we can see. The Clavius impact just so happens to have occurred at a position that from our viewing angle appears to be centrally located in that older structure. Of course this whole speculation could go down the drain if there were some altimetry available of the region :>)

Rick, the classic on multi-ring basins is Paul Spudis' 1993 book on that subject. I think it is pretty "readable" but you may or may not agree. it isn't too expensive in any case.

Jim, I am pretty sure there is a good deal of high quality altimetry currently available re; the Clavius region, most recently from LRO-LOLA, which has, as far as i know, mapped the entire moon to date. There could be an old basin there and Clavius could have landed later right in the center of it...but the jumbled nature of the highlands area of the Moon makes any assertions re; probability about that pretty difficult to attain... I haven't seen any such assertions in the literature about it..but that doesn't mean there never will be.

I just got a copy of Dinsmore Alter's "Lunar Atlas" today (what an excellent atlas!), and it deals with the Clavius area on pages 224-227. Alter deals extensively with "my" ring structure, even delineating it with references on the photos. So, I'm not the only one who's seen it.

I got my copy of this atlas for $7, delivered to my house. If you don't have one, you should check it out.